chrony/reference.c
Richard P. Curnow 8884034104 Equivalent to V1.19.99.1
This is a verbatim copy of the files at that stage of the repository that was
built from the CVS import.  It allows future development to see a bit of recent
history, but without carrying around the baggage going back to 1997.  If that
is really required, git grafts can be used.
2006-01-19 21:34:28 +00:00

709 lines
19 KiB
C

/*
$Header: /cvs/src/chrony/reference.c,v 1.40 2003/03/24 23:35:43 richard Exp $
=======================================================================
chronyd/chronyc - Programs for keeping computer clocks accurate.
**********************************************************************
* Copyright (C) Richard P. Curnow 1997-2002
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*
**********************************************************************
=======================================================================
This module keeps track of the source which we are claiming to be
our reference, for the purposes of generating outgoing NTP packets */
#include "sysincl.h"
#include "memory.h"
#include "reference.h"
#include "util.h"
#include "conf.h"
#include "logging.h"
#include "local.h"
#include "mkdirpp.h"
/* ================================================== */
static int are_we_synchronised;
static int enable_local_stratum;
static int local_stratum;
static NTP_Leap our_leap_status;
static int our_stratum;
static unsigned long our_ref_id;
struct timeval our_ref_time; /* Stored relative to reference, NOT local time */
static double our_offset;
static double our_skew;
static double our_residual_freq;
static double our_root_delay;
static double our_root_dispersion;
static double max_update_skew;
/* Flag indicating that we are initialised */
static int initialised = 0;
/* Flag and threshold for logging clock changes to syslog */
static int do_log_change;
static double log_change_threshold;
/* Flag, threshold and user for sending mail notification on large clock changes */
static int do_mail_change;
static double mail_change_threshold;
static char *mail_change_user;
/* Filename of the drift file. */
static char *drift_file=NULL;
static void update_drift_file(double, double);
#define MAIL_PROGRAM "/usr/lib/sendmail"
/* ================================================== */
/* File to which statistics are logged, NULL if none */
static FILE *logfile = NULL;
static char *logfilename = NULL;
static unsigned long logwrites = 0;
#define TRACKING_LOG "tracking.log"
/* ================================================== */
/* Day number of 1 Jan 1970 */
#define MJD_1970 40587
/* Reference ID supplied when we are locally referenced */
#define LOCAL_REFERENCE_ID 0x7f7f0101UL
/* ================================================== */
void
REF_Initialise(void)
{
char *direc;
FILE *in;
char line[1024];
double file_freq_ppm, file_skew_ppm;
double our_frequency_ppm;
are_we_synchronised = 0;
our_leap_status = LEAP_Normal;
initialised = 1;
our_root_dispersion = 1.0;
our_root_delay = 1.0;
our_frequency_ppm = 0.0;
our_skew = 1.0; /* i.e. rather bad */
our_residual_freq = 0.0;
/* Now see if we can get the drift file opened */
drift_file = CNF_GetDriftFile();
if (drift_file) {
in = fopen(drift_file, "r");
if (in) {
if (fgets(line, sizeof(line), in)) {
if (sscanf(line, "%lf%lf", &file_freq_ppm, &file_skew_ppm) == 2) {
/* We have read valid data */
our_frequency_ppm = file_freq_ppm;
our_skew = 1.0e-6 * file_skew_ppm;
} else {
LOG(LOGS_WARN, LOGF_Reference, "Could not parse valid frequency and skew from driftfile %s",
drift_file);
}
} else {
LOG(LOGS_WARN, LOGF_Reference, "Could not read valid frequency and skew from driftfile %s",
drift_file);
}
fclose(in);
} else {
LOG(LOGS_WARN, LOGF_Reference, "Could not open driftfile %s for reading",
drift_file);
}
update_drift_file(our_frequency_ppm,our_skew);
}
LCL_SetAbsoluteFrequency(our_frequency_ppm);
if (CNF_GetLogTracking()) {
direc = CNF_GetLogDir();
if (!mkdir_and_parents(direc)) {
LOG(LOGS_ERR, LOGF_Reference, "Could not create directory %s", direc);
logfile = NULL;
} else {
logfilename = MallocArray(char, 2 + strlen(direc) + strlen(TRACKING_LOG));
strcpy(logfilename, direc);
strcat(logfilename, "/");
strcat(logfilename, TRACKING_LOG);
logfile = fopen(logfilename, "a");
if (!logfile) {
LOG(LOGS_WARN, LOGF_Reference, "Couldn't open logfile %s for update", logfilename);
}
}
}
max_update_skew = fabs(CNF_GetMaxUpdateSkew()) * 1.0e-6;
enable_local_stratum = CNF_AllowLocalReference(&local_stratum);
CNF_GetLogChange(&do_log_change, &log_change_threshold);
CNF_GetMailOnChange(&do_mail_change, &mail_change_threshold, &mail_change_user);
/* And just to prevent anything wierd ... */
if (do_log_change) {
log_change_threshold = fabs(log_change_threshold);
}
return;
}
/* ================================================== */
void
REF_Finalise(void)
{
if (logfile) {
fclose(logfile);
}
initialised = 0;
return;
}
/* ================================================== */
static double
Sqr(double x)
{
return x*x;
}
/* ================================================== */
#if 0
static double
Cube(double x)
{
return x*x*x;
}
#endif
/* ================================================== */
/* Update the drift coefficients to the file. */
static void
update_drift_file(double freq_ppm, double skew)
{
struct stat buf;
char *temp_drift_file;
FILE *out;
/* Create a temporary file with a '.tmp' extension. */
temp_drift_file = (char*) Malloc(strlen(drift_file)+8);
if(!temp_drift_file) {
return;
}
strcpy(temp_drift_file,drift_file);
strcat(temp_drift_file,".tmp");
out = fopen(temp_drift_file, "w");
if (!out) {
Free(temp_drift_file);
LOG(LOGS_WARN, LOGF_Reference, "Could not open temporary driftfile %s.tmp for writing",
drift_file);
return;
}
/* Write the frequency and skew parameters in ppm */
fprintf(out, "%20.4f %20.4f\n", freq_ppm, 1.0e6 * skew);
fclose(out);
/* Clone the file attributes from the existing file if there is one. */
if (!stat(drift_file,&buf)) {
chown(temp_drift_file,buf.st_uid,buf.st_gid);
chmod(temp_drift_file,buf.st_mode&0777);
}
/* Rename the temporary file to the correct location (see rename(2) for details). */
if (rename(temp_drift_file,drift_file)) {
unlink(temp_drift_file);
Free(temp_drift_file);
LOG(LOGS_WARN, LOGF_Reference, "Could not replace old driftfile %s with new one %s.tmp (%d)",
drift_file,drift_file);
return;
}
Free(temp_drift_file);
}
/* ================================================== */
#define BUFLEN 255
#define S_MAX_USER_LEN "128"
static void
maybe_log_offset(double offset)
{
double abs_offset;
FILE *p;
char buffer[BUFLEN], host[BUFLEN];
time_t now;
struct tm stm;
abs_offset = fabs(offset);
if (do_log_change &&
(abs_offset > log_change_threshold)) {
LOG(LOGS_WARN, LOGF_Reference,
"System clock wrong by %.6f seconds, adjustment started",
-offset);
}
if (do_mail_change &&
(abs_offset > mail_change_threshold)) {
sprintf(buffer, "%s %." S_MAX_USER_LEN "s", MAIL_PROGRAM, mail_change_user);
p = popen(buffer, "w");
if (p) {
if (gethostname(host, sizeof(host)) < 0) {
strcpy(host, "<UNKNOWN>");
}
fprintf(p, "Subject: chronyd reports change to system clock on node [%s]\n", host);
fputs("\n", p);
now = time(NULL);
stm = *localtime(&now);
strftime(buffer, sizeof(buffer), "On %A, %d %B %Y\n with the system clock reading %H:%M:%S (%Z)", &stm);
fputs(buffer, p);
/* If offset < 0 the local clock is slow, so we are applying a
positive change to it to bring it into line, hence the
negation of 'offset' in the next statement (and earlier) */
fprintf(p,
"\n\nchronyd started to apply an adjustment of %.3f seconds to it,\n"
" which exceeded the reporting threshold of %.3f seconds\n\n",
-offset, mail_change_threshold);
pclose(p);
} else {
LOG(LOGS_ERR, LOGF_Reference,
"Could not send mail notification to user %s\n",
mail_change_user);
}
}
}
/* ================================================== */
void
REF_SetReference(int stratum,
NTP_Leap leap,
unsigned long ref_id,
struct timeval *ref_time,
double offset,
double frequency,
double skew,
double root_delay,
double root_dispersion
)
{
double previous_skew, new_skew;
double previous_freq, new_freq;
double old_weight, new_weight, sum_weight;
double delta_freq1, delta_freq2;
double skew1, skew2;
double our_frequency;
double abs_freq_ppm;
assert(initialised);
/* If we get a serious rounding error in the source stats regression
processing, there is a remote chance that the skew argument is a
'not a number'. If such a quantity gets propagated into the
machine's kernel clock variables, nasty things will happen ..
To guard against this we need to check whether the skew argument
is a reasonable real number. I don't think isnan, isinf etc are
platform independent, so the following algorithm is used. */
{
double t;
t = (skew + skew) / skew; /* Skew shouldn't be zero either */
if ((t < 1.9) || (t > 2.1)) {
LOG(LOGS_WARN, LOGF_Reference, "Bogus skew value encountered");
return;
}
}
are_we_synchronised = 1;
our_stratum = stratum + 1;
our_leap_status = leap;
our_ref_id = ref_id;
our_ref_time = *ref_time;
our_offset = offset;
our_root_delay = root_delay;
our_root_dispersion = root_dispersion;
/* Eliminate updates that are based on totally unreliable frequency
information */
if (fabs(skew) < max_update_skew) {
previous_skew = our_skew;
new_skew = skew;
previous_freq = 0.0; /* We assume that the local clock is running
according to our previously determined
value; note that this is a delta frequency
--- absolute frequencies are only known in
the local module. */
new_freq = frequency;
/* Set new frequency based on weighted average of old and new skew. */
old_weight = 1.0 / Sqr(previous_skew);
new_weight = 3.0 / Sqr(new_skew);
sum_weight = old_weight + new_weight;
our_frequency = (previous_freq * old_weight + new_freq * new_weight) / sum_weight;
delta_freq1 = previous_freq - our_frequency;
delta_freq2 = new_freq - our_frequency;
skew1 = sqrt((Sqr(delta_freq1) * old_weight + Sqr(delta_freq2) * new_weight) / sum_weight);
skew2 = (previous_skew * old_weight + new_skew * new_weight) / sum_weight;
our_skew = skew1 + skew2;
our_residual_freq = new_freq - our_frequency;
maybe_log_offset(our_offset);
LCL_AccumulateFrequencyAndOffset(our_frequency, our_offset);
} else {
#if 0
LOG(LOGS_INFO, LOGF_Reference, "Skew %f too large to track, offset=%f", skew, our_offset);
#endif
maybe_log_offset(our_offset);
LCL_AccumulateOffset(our_offset);
our_residual_freq = frequency;
}
abs_freq_ppm = LCL_ReadAbsoluteFrequency();
if (logfile) {
if (((logwrites++) % 32) == 0) {
fprintf(logfile,
"=======================================================================\n"
" Date (UTC) Time IP Address St Freq ppm Skew ppm Offset\n"
"=======================================================================\n");
}
fprintf(logfile, "%s %-15s %2d %10.3f %10.3f %10.3e\n",
UTI_TimeToLogForm(ref_time->tv_sec),
UTI_IPToDottedQuad(our_ref_id),
our_stratum,
abs_freq_ppm,
1.0e6*our_skew,
our_offset);
fflush(logfile);
}
if (drift_file) {
update_drift_file(abs_freq_ppm, our_skew);
}
/* And now set the freq and offset to zero */
our_frequency = 0.0;
our_offset = 0.0;
return;
}
/* ================================================== */
void
REF_SetManualReference
(
struct timeval *ref_time,
double offset,
double frequency,
double skew
)
{
int millisecond;
double abs_freq_ppm;
/* We are not synchronised to an external source, as such. This is
only supposed to be used with the local source option, really
... */
are_we_synchronised = 0;
our_skew = skew;
our_residual_freq = 0.0;
maybe_log_offset(offset);
LCL_AccumulateFrequencyAndOffset(frequency, offset);
abs_freq_ppm = LCL_ReadAbsoluteFrequency();
if (logfile) {
millisecond = ref_time->tv_usec / 1000;
fprintf(logfile, "%5s %-15s %2d %10.3f %10.3f %10.3e\n",
UTI_TimeToLogForm(ref_time->tv_sec),
"127.127.1.1",
our_stratum,
abs_freq_ppm,
1.0e6*our_skew,
our_offset);
fflush(logfile);
}
if (drift_file) {
update_drift_file(abs_freq_ppm, our_skew);
}
}
/* ================================================== */
void
REF_SetUnsynchronised(void)
{
/* Variables required for logging to statistics log */
int millisecond;
struct timeval now;
double local_clock_err;
assert(initialised);
if (logfile) {
LCL_ReadCookedTime(&now, &local_clock_err);
millisecond = now.tv_usec / 1000;
fprintf(logfile, "%s %-15s 0 %10.3f %10.3f %10.3e\n",
UTI_TimeToLogForm(now.tv_sec),
"0.0.0.0",
LCL_ReadAbsoluteFrequency(),
1.0e6*our_skew,
0.0);
fflush(logfile);
}
are_we_synchronised = 0;
}
/* ================================================== */
void
REF_GetReferenceParams
(
struct timeval *local_time,
int *is_synchronised,
NTP_Leap *leap_status,
int *stratum,
unsigned long *ref_id,
struct timeval *ref_time,
double *root_delay,
double *root_dispersion
)
{
double elapsed;
double extra_dispersion;
assert(initialised);
if (are_we_synchronised) {
*is_synchronised = 1;
*stratum = our_stratum;
UTI_DiffTimevalsToDouble(&elapsed, local_time, &our_ref_time);
extra_dispersion = (our_skew + fabs(our_residual_freq)) * elapsed;
*leap_status = our_leap_status;
*ref_id = our_ref_id;
*ref_time = our_ref_time;
*root_delay = our_root_delay;
*root_dispersion = our_root_dispersion + extra_dispersion;
} else if (enable_local_stratum) {
*is_synchronised = 1;
*stratum = local_stratum;
*ref_id = LOCAL_REFERENCE_ID;
/* Make the reference time be now less a second - this will
scarcely affect the client, but will ensure that the transmit
timestamp cannot come before this (which would cause test 6 to
fail in the client's read routine) if the local system clock's
read routine is broken in any way. */
*ref_time = *local_time;
--ref_time->tv_sec;
/* Not much else we can do for leap second bits - maybe need to
have a way for the administrator to feed leap bits in */
*leap_status = LEAP_Normal;
*root_delay = 0.0;
*root_dispersion = LCL_GetSysPrecisionAsQuantum();
} else {
*is_synchronised = 0;
*leap_status = LEAP_Unsynchronised;
*stratum = 0;
*ref_id = 0UL;
ref_time->tv_sec = ref_time->tv_usec = 0;
/* These values seem to be standard for a client, and
any peer or client of ours will ignore them anyway because
we don't claim to be synchronised */
*root_dispersion = 1.0;
*root_delay = 1.0;
}
}
/* ================================================== */
int
REF_GetOurStratum(void)
{
if (are_we_synchronised) {
return our_stratum;
} else if (enable_local_stratum) {
return local_stratum;
} else {
return 16;
}
}
/* ================================================== */
void
REF_ModifyMaxupdateskew(double new_max_update_skew)
{
max_update_skew = new_max_update_skew * 1.0e-6;
#if 0
LOG(LOGS_INFO, LOGF_Reference, "New max update skew = %.3fppm", new_max_update_skew);
#endif
}
/* ================================================== */
void
REF_EnableLocal(int stratum)
{
enable_local_stratum = 1;
local_stratum = stratum;
}
/* ================================================== */
void
REF_DisableLocal(void)
{
enable_local_stratum = 0;
}
/* ================================================== */
void
REF_GetTrackingReport(RPT_TrackingReport *rep)
{
double elapsed;
double extra_dispersion;
struct timeval now_raw, now_cooked;
double correction;
LCL_ReadRawTime(&now_raw);
correction = LCL_GetOffsetCorrection(&now_raw);
UTI_AddDoubleToTimeval(&now_raw, correction, &now_cooked);
if (are_we_synchronised) {
UTI_DiffTimevalsToDouble(&elapsed, &now_cooked, &our_ref_time);
extra_dispersion = (our_skew + fabs(our_residual_freq)) * elapsed;
rep->ref_id = our_ref_id;
rep->stratum = our_stratum;
rep->ref_time = our_ref_time;
UTI_DoubleToTimeval(correction, &rep->current_correction);
rep->freq_ppm = LCL_ReadAbsoluteFrequency();
rep->resid_freq_ppm = 1.0e6 * our_residual_freq;
rep->skew_ppm = 1.0e6 * our_skew;
rep->root_delay = our_root_delay;
rep->root_dispersion = our_root_dispersion + extra_dispersion;
} else if (enable_local_stratum) {
rep->ref_id = LOCAL_REFERENCE_ID;
rep->stratum = local_stratum;
rep->ref_time = now_cooked;
UTI_DoubleToTimeval(correction, &rep->current_correction);
rep->freq_ppm = LCL_ReadAbsoluteFrequency();
rep->resid_freq_ppm = 0.0;
rep->skew_ppm = 0.0;
rep->root_delay = 0.0;
rep->root_dispersion = LCL_GetSysPrecisionAsQuantum();
} else {
rep->ref_id = 0UL;
rep->stratum = 0;
rep->ref_time.tv_sec = 0;
rep->ref_time.tv_usec = 0;
UTI_DoubleToTimeval(correction, &rep->current_correction);
rep->freq_ppm = LCL_ReadAbsoluteFrequency();
rep->resid_freq_ppm = 0.0;
rep->skew_ppm = 0.0;
rep->root_delay = 0.0;
rep->root_dispersion = 0.0;
}
}
/* ================================================== */
void
REF_CycleLogFile(void)
{
if (logfile && logfilename) {
fclose(logfile);
logfile = fopen(logfilename, "a");
if (!logfile) {
LOG(LOGS_WARN, LOGF_Reference, "Could not reopen logfile %s", logfilename);
}
logwrites = 0;
}
}
/* ================================================== */